EP0902585A2 - Procédé et appareil de traitement d'image - Google Patents

Procédé et appareil de traitement d'image Download PDF

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Publication number
EP0902585A2
EP0902585A2 EP98116003A EP98116003A EP0902585A2 EP 0902585 A2 EP0902585 A2 EP 0902585A2 EP 98116003 A EP98116003 A EP 98116003A EP 98116003 A EP98116003 A EP 98116003A EP 0902585 A2 EP0902585 A2 EP 0902585A2
Authority
EP
European Patent Office
Prior art keywords
feature parameter
region
image
image processing
processing apparatus
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP98116003A
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German (de)
English (en)
Other versions
EP0902585A3 (fr
EP0902585B1 (fr
Inventor
Yasushi Adachi
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Sharp Corp
Original Assignee
Sharp Corp
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Filing date
Publication date
Application filed by Sharp Corp filed Critical Sharp Corp
Publication of EP0902585A2 publication Critical patent/EP0902585A2/fr
Publication of EP0902585A3 publication Critical patent/EP0902585A3/fr
Application granted granted Critical
Publication of EP0902585B1 publication Critical patent/EP0902585B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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Classifications

    • H—ELECTRICITY
    • H04—ELECTRIC COMMUNICATION TECHNIQUE
    • H04N—PICTORIAL COMMUNICATION, e.g. TELEVISION
    • H04N1/00—Scanning, transmission or reproduction of documents or the like, e.g. facsimile transmission; Details thereof
    • H04N1/40—Picture signal circuits
    • H04N1/40062—Discrimination between different image types, e.g. two-tone, continuous tone

Definitions

  • the image processing apparatus carries out image processing so as to improve the image quality of a recorded image obtained from the image signal. For example, when the image is characters, an enhancement process is carried out to enhance the edges of the image, and when the image is halftone dots, a smoothing process is carried out so as to prevent moire. Also, when the image is characters, it is a common practice to carry out a process for converting the image into a character code.
  • the present invention offers a solution to the above-mentioned problems, and accordingly it is an object of the present invention to provide an image processing apparatus capable of discriminating a character region, a photographic region, and a halftone dot region of an image with certainty, and a recording medium recording a program for image processing.
  • the image processing as described above having such a desirable characteristic is carried out by execution of a program recorded on a recording medium as described below.
  • the image signal inputted into the input terminal 1 a variety of image signals are possible. However, here, as an example, explanations will be given through the case where the image signal is obtained by reading of a document by an image reading section (not shown) having a CCD (Charge Coupled Device) image sensor in a digital copying machine or a facsimile device.
  • CCD Charge Coupled Device
  • the judging circuit 6 selects whether the region including the target pixel is the character region, the photographic region, or the halftone dot region, namely, a discrimination signal Oa in accordance with each region type is outputted as region discrimination information.
  • 3 bits are used as an output value indicative of the likelihood of the character region, and 2 bits (Ob 10 and Ob 11 ) are used as an output value indicative of the likelihood of the photographic region, and 3 bits (Ob 20 to Ob 22 ) are used as an output value indicative of the likelihood of the halftone dot region.
  • the explanations are given through the case where the second feature parameter calculating circuit 4 is provided with the main difference value calculating circuit 41a and the sub difference value calculating circuit 41b, and the sum of difference values is calculated with respect to each of the main scanning direction and the sub scanning direction.
  • the diagonal directions two directions of right diagonal 45° direction and left diagonal 45° direction are adopted; however, as long as the diagonal directions are different from the main scanning direction and the sub scanning direction, the number and the degree of slope of the diagonal directions are not limited. Nevertheless, when the right diagonal 45° direction and the left diagonal 45° direction are adopted as the diagonal directions, the directions of detecting the edge component are situated evenly. This allows the discrimination accuracy for the character region to be further improved.
  • a filtering process circuit 8c as described below is adopted as the filtering process circuit 8. This allows the filtering process to be carried out by determining optimum filter coefficients for the target pixel.
  • the weight coefficient W e of the enhancement filter and the weight coefficient W s of the smoothing filter are determined from the following Equations of (3) and (4), respectively.
  • W e g 1 (O c )
  • W s g 2 (O s )
  • the third feature parameter P 3 is calculated in accordance with the image of a binarized local block.
  • the contrast is low as in a region composed of fine halftone dots, there is a case where the same value is given to adjacent pixels due to binarization.
  • a density slope exists in an image, in one portion of the local block, for example, in the upper half portion, all the pixels therein take one of the binary values, and in the other portion of the local block, all the pixels therein take the other binary value.
  • the third feature parameter P 3 is increased, and it becomes difficult to distinguish this region from the character region.
  • the third feature parameter P 3 is calculated in accordance with the succession in the main scanning direction and the succession in the sub scanning direction, the possibility of erroneously discriminating characters having diagonal lines as the halftone dot region is relatively high. The occurrence of this error is increased as the size of characters is increased. Therefore, as in Second Embodiment, by proving the second feature parameter calculating circuit 4a with the diagonal direction difference value calculating circuit 41c (41d), it is further ensured that the region composed of large characters is not discriminated erroneously.
  • the image processing apparatus in accordance with the present invention in addition to the arrangement including the complexity feature parameter calculating means, may have an arrangement wherein the main direction and the sub direction are substantially orthogonal to each other, and the complexity feature parameter calculating means further calculates the sum of the differences in signal level with respect to diagonal directions different from the main direction and the sub direction so as to output the minimum value of the sums in the main direction, the sub direction, and the diagonal directions.
  • the main direction calculating section calculates the sum of calculated maximum values per not less than two main lines
  • the sub direction calculating section calculates the sum of calculated maximum values per not less than two sub lines.
  • the discriminating means outputs the degree of likelihood that the region including the target pixel is the character region or the halftone dot region.
  • the discriminating means can send more delicate instructions to means for processing an inputted image, for example, means for carrying out spacial filtering, which is provided on the following stage of the discriminating means.
  • the program is for carrying out the steps of: (1) calculating, per main line along the main direction, with respect to a binary image which has been prepared by binarizing the pixels in the local block with a predetermined threshold value, the maximum value of the numbers of succeeding pixels having equal value, and determining the sum of calculated values per at least one main line succeeding in the sub direction, so as to determine a difference of the maximum value and the minimum value of the sums; (2) calculating, per sub line along the sub direction, with respect to the binary image, the maximum value of the numbers of succeeding pixels having equal value, and determining the sum of calculated values per at least one sub line succeeding in the main direction, so as to determine a difference of the maximum value and the minimum value of the sums; (3) calculating the maximum value of the differences determined in the step (1) and in the step (2) as a variable of the succession feature parameter; and (4) calculating the region discrimination information of the region including the target pixel.

Landscapes

  • Engineering & Computer Science (AREA)
  • Multimedia (AREA)
  • Signal Processing (AREA)
  • Facsimile Image Signal Circuits (AREA)
  • Image Analysis (AREA)
EP98116003A 1997-09-11 1998-08-25 Procédé et appareil de traitement d'image Expired - Lifetime EP0902585B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP24733597A JP3512604B2 (ja) 1997-09-11 1997-09-11 画像処理装置、および、そのプログラムを記録した記録媒体
JP24733597 1997-09-11
JP247335/97 1997-09-11

Publications (3)

Publication Number Publication Date
EP0902585A2 true EP0902585A2 (fr) 1999-03-17
EP0902585A3 EP0902585A3 (fr) 1999-12-08
EP0902585B1 EP0902585B1 (fr) 2002-11-06

Family

ID=17161884

Family Applications (1)

Application Number Title Priority Date Filing Date
EP98116003A Expired - Lifetime EP0902585B1 (fr) 1997-09-11 1998-08-25 Procédé et appareil de traitement d'image

Country Status (4)

Country Link
US (1) US6111982A (fr)
EP (1) EP0902585B1 (fr)
JP (1) JP3512604B2 (fr)
DE (1) DE69809164T2 (fr)

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1058448A2 (fr) 1999-05-31 2000-12-06 Sharp Kabushiki Kaisha Appareil de traítement d'images
EP1079601A1 (fr) * 1999-03-05 2001-02-28 Seiko Epson Corporation Correcteur de donnees d'image, procede de correction de donnees d'image, support sur lequel est enregistre le programme de correction de donnees d'image
WO2002080525A3 (fr) * 2001-03-28 2003-03-13 Koninkl Philips Electronics Nv Systeme et procede d'accentuation par segmentation d'une image video
US6965696B1 (en) 1999-10-14 2005-11-15 Sharp Kabushiki Kaisha Image processing device for image region discrimination

Families Citing this family (9)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP3639452B2 (ja) * 1999-02-12 2005-04-20 シャープ株式会社 画像処理装置
JP2000333014A (ja) * 1999-05-20 2000-11-30 Minolta Co Ltd 画像処理装置および画像処理方法並びに画像処理手順を記憶したコンピュータ読み取り可能な記憶媒体
JP2002247025A (ja) * 2001-02-22 2002-08-30 Hitachi Ltd 情報処理装置
US6690828B2 (en) * 2001-04-09 2004-02-10 Gary Elliott Meyers Method for representing and comparing digital images
CN100405388C (zh) * 2004-05-14 2008-07-23 欧姆龙株式会社 特定被摄体检测装置
US20060165287A1 (en) * 2005-01-27 2006-07-27 Destiny Technology Corporation Photo and text discriminating method
JP4135752B2 (ja) * 2006-06-12 2008-08-20 コニカミノルタビジネステクノロジーズ株式会社 画像処理装置、画像処理方法及び画像処理プログラム
JP4963645B2 (ja) * 2007-07-27 2012-06-27 キヤノン株式会社 画像処理装置及び方法
KR101214772B1 (ko) * 2010-02-26 2012-12-21 삼성전자주식회사 문자의 방향성을 기반으로 한 문자 인식 장치 및 방법

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EP0100811A2 (fr) * 1982-08-18 1984-02-22 International Business Machines Corporation Appareil pour la reproduction d'originaux à tons divers et à lignes et sa méthode de fonctionnement
US4786820A (en) * 1984-12-14 1988-11-22 Canon Kabushiki Kaisha Apparatus for parallel-processing image data
US5016118A (en) * 1988-09-22 1991-05-14 Kabushiki Kaisha Toshiba Image determining method and apparatus
EP0710004A2 (fr) * 1994-10-27 1996-05-01 Sharp Kabushiki Kaisha Appareil de traitement d'images
US5867593A (en) * 1993-10-20 1999-02-02 Olympus Optical Co., Ltd. Image region dividing apparatus

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US4907285A (en) * 1984-08-24 1990-03-06 Hitachi, Ltd. Image understanding system
GB2170373B (en) * 1984-12-28 1989-03-15 Canon Kk Image processing apparatus
DE3686821T2 (de) * 1985-01-10 1993-04-01 Nippon Telegraph & Telephone Halbtonbildverarbeitungseinrichtung.
JPS63246076A (ja) * 1987-03-31 1988-10-13 Fuji Xerox Co Ltd フイルタ処理装置
JP2702928B2 (ja) * 1987-06-19 1998-01-26 株式会社日立製作所 画像入力装置
US5001767A (en) * 1987-11-30 1991-03-19 Kabushiki Kaisha Toshiba Image processing device
JP2513002B2 (ja) * 1988-10-31 1996-07-03 富士ゼロックス株式会社 中間調画像生成装置
EP0392701B1 (fr) * 1989-04-10 1995-11-08 Canon Kabushiki Kaisha Dispositif pour la réduction d'images
US5195147A (en) * 1989-05-02 1993-03-16 Ricoh Company, Ltd. Image forming apparatus
US5668646A (en) * 1990-02-06 1997-09-16 Canon Kabushiki Kaisha Apparatus and method for decoding differently encoded multi-level and binary image data, the later corresponding to a color in the original image
JP3437226B2 (ja) * 1993-10-20 2003-08-18 キヤノン株式会社 画像処理方法及び装置
JP3636332B2 (ja) * 1993-12-24 2005-04-06 セイコーエプソン株式会社 画像処理方法および画像処理装置
JP3215768B2 (ja) * 1994-03-24 2001-10-09 株式会社東芝 画像処理装置
US5587808A (en) * 1994-05-31 1996-12-24 Nec Corporation Image processing apparatus for identifying character, photo and dot images in image area
US5729627A (en) * 1994-11-16 1998-03-17 Mita Industrial Co., Ltd. Apparatus for and method of judging dotted image area

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0100811A2 (fr) * 1982-08-18 1984-02-22 International Business Machines Corporation Appareil pour la reproduction d'originaux à tons divers et à lignes et sa méthode de fonctionnement
US4786820A (en) * 1984-12-14 1988-11-22 Canon Kabushiki Kaisha Apparatus for parallel-processing image data
US5016118A (en) * 1988-09-22 1991-05-14 Kabushiki Kaisha Toshiba Image determining method and apparatus
US5867593A (en) * 1993-10-20 1999-02-02 Olympus Optical Co., Ltd. Image region dividing apparatus
EP0710004A2 (fr) * 1994-10-27 1996-05-01 Sharp Kabushiki Kaisha Appareil de traitement d'images

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP1079601A1 (fr) * 1999-03-05 2001-02-28 Seiko Epson Corporation Correcteur de donnees d'image, procede de correction de donnees d'image, support sur lequel est enregistre le programme de correction de donnees d'image
EP1079601A4 (fr) * 1999-03-05 2004-06-16 Seiko Epson Corp Correcteur de donnees d'image, procede de correction de donnees d'image, support sur lequel est enregistre le programme de correction de donnees d'image
US7110599B1 (en) 1999-03-05 2006-09-19 Seiko Epson Corporation Image data retouching apparatus, image data retouching method, and medium on which image data retouching program is recorded
EP1058448A2 (fr) 1999-05-31 2000-12-06 Sharp Kabushiki Kaisha Appareil de traítement d'images
EP1058448A3 (fr) * 1999-05-31 2003-01-15 Sharp Kabushiki Kaisha Appareil de traítement d'images
US6728425B1 (en) 1999-05-31 2004-04-27 Sharp Kabushiki Kaisha Image processing device
US6965696B1 (en) 1999-10-14 2005-11-15 Sharp Kabushiki Kaisha Image processing device for image region discrimination
WO2002080525A3 (fr) * 2001-03-28 2003-03-13 Koninkl Philips Electronics Nv Systeme et procede d'accentuation par segmentation d'une image video
US6903782B2 (en) 2001-03-28 2005-06-07 Koninklijke Philips Electronics N.V. System and method for performing segmentation-based enhancements of a video image
KR100853954B1 (ko) * 2001-03-28 2008-08-25 코닌클리케 필립스 일렉트로닉스 엔.브이. 비디오 화상의 분할-기반의 강조 수행 시스템 및 방법
CN100490533C (zh) * 2001-03-28 2009-05-20 皇家菲利浦电子有限公司 用于执行基于分段的视频图象的增强的系统和方法

Also Published As

Publication number Publication date
EP0902585A3 (fr) 1999-12-08
DE69809164D1 (de) 2002-12-12
US6111982A (en) 2000-08-29
EP0902585B1 (fr) 2002-11-06
JP3512604B2 (ja) 2004-03-31
DE69809164T2 (de) 2003-07-24
JPH1188664A (ja) 1999-03-30

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